Inhibiting mold in dairy products



, Patentedec, l7, ldfi rarsur orrlcs INITING MOLD IN DAIRY PRGEDIJCISHans F. Bauer and Elmer F. Glabe, Chicago, Ill., assignors, by mesneassignments, to Stein, Hall & 00., Inc., a corporation of New York NoDrawing.

6 Claims.

' to inhibit or retard the development and growth of micro-organismssuch as bacteria and molds commonly found in such products.

One of the objects of the present invention is to provide a new andimproved type of compo sition for inhibiting or retarding the growth anddevelopment of food destroying bacteria and molds commonly found inmilk, cheese, butter, buttermilk and other dairy products.

Another object of the invention is to provide a new and improved methodfor treating milk, butter, cheese, buttermilk and other dairy productsin order to retard or to inhibit the growth and development of fooddestroying bacteria and molds.

Other objects and advantages of the invention will appear from thefollowing description thereof.

In accordance with the invention, it has been found that a particularclass or type of agent comprising an acetate containing combined butundissociated acetic acid in its molecule, and preferably sodiumdiacetate having the formula:

2(CH3COONa) .2(CH3COOH) .HzO

has the property of retarding, inhibiting and preventing the growth anddevelopment of microorganisms such as bacteria and molds commonly foundin dairy products such a milk, butter, cheese, buttermilk and other milkderived products. One of the features of the invention is that only avery small amount of the bacteria and mold inhibiting composition isrequired to prevent the action of the food destroying bacteria and moldsand to retain the dairy products in a usable state over a substantialperiod of time. Another feature of the invention is that the bacteriaand mold inhibiting composition does not substantially affect the taste,food value or other properties of the dairy products.

The invention will be further illustrated, but is not limited by thefollowing examples in which the quantities are stated in parts byweight, unless otherwise indicated:

Application February 2, 1942, Serial No. 429,286

Example I In this example the dairy product treated was butter. Butteris ordinarily sold in a wrapped form and there is often a tendency formold to develop between the butter and the wrapper, particularly when asubstantial amount of moisture is present, as is usually the case.

In the present example, the parchment paper normally used to wrap butterwas dipped for 2 minutes in a cold solution made by blending togetherparts of sodium diacetate and 20 parts of potato starch, then mixing theblend with sufficient water to form a 5% solution and cooking themixture by heating to a temperature of F. until a uniform dispersion wasobtained. After cooking, the dispersion was allowed to cool andthereafter the parchment paper was dipped in v the dispersion, aspreviously indicated.

The paper thus treated was then used to wrap butter in the usual mannerand a series of tests was made in order to demonstrate the bacteria andmold inhibiting properties of the treating composition.

These tests were conducted as follows: The test apparatus was sterilizedby heating, a glass test vessel being employed. Four such test vesselswere used and in the first there was placed a piece of wet parchmentpaper of the type used in wrapping the butter, but which had not beentreated in any way. In the second vessel there was placeda sample ofbutter wrapped in the same type of parchment paper which was placed inthe first vessel. The second sample likewise was not treated in any way.In the third vessel there was placed a sample of paper which had beencoated by dipping in themanner previously described in a dispersion ofsodium diacetate and potato starch. was placed a sample of butterwrapped with a. sample of the treated paper of the same type used in thethird test vessel.

None of the samples exhibited any mold growth on the 15th day aftertheir preparation. on the 15th day all samples were inoculated withcommon molds such as Rhizopus nigrican-s, Penicillium, etc. The sampleshad all been stored in a refrigerator at 40 F. the first 9 days and fromthen on the temperature was room temperature, around 75 F.

The first and second control samples showed pronounced mold growth onthe 21st day. The third sample, that is, the parchment paper coated withthe inhibiting composition, showed slight mold growth on the 31st dayand the fourth sam- In the fourth test vessel there 3 ple, that is, thebutter treated with the inhibiting composition by being wrapped with thecoated paper, showed slight mold growth on the 28th day.

Example II In this example the procedure was the same as in Example Iexcept that the inoculation was made with molds grown on whey instead ofthe common molds used in Example I. In this example the paper, the testvessel and the butter were all sterilized by heating. The results weresubstantially the same as in Example I. The purpose of this example wasto demonstrate that the invention was effective with molds common todairy products. Example I indicates the effectiveness of the inventionwith other common molds.

Example III In this example the product treated was a cheese of the typeknown as spread cheese, that is to say, a cheese which is suitable forspreading on bread, crackers, or the like. Sodium diacetate wasincorporated directly into the cheese and intimately mixed therewith inproportions of about I%% to around 2%. The control containing no sodiumdiacetate showed signs of mold in about 3 days and the treated cheesewas still good after days.

It will be understood that the foregoing examples are merelyillustrative and not limitative. The invention is applicable in thetreatment of all dairy products. Where the dairy product is a pressedcheese, the sodium diacetate may be applied by dipping the cheese in asolution of sodium diacetate or in a coating composition containingsodium diacetate and then applying a wrapper. This treatment willsubstantially inhibit or retard the growth and development of moldbetween the cheese and the Wrapper, which is the point where it usuallyoccurs. Among the various types of cheese which may be treated in thismanner are American cheese, Swiss cheese, and other types of cheesenormally sold in a relatively large bulk. It is also desirable, inaccordance with the invention, to apply the sodium diacetate or acoating composition containing sodium diacetate, such as that describedin Example I, to the cloth which is used to wrap the cheese. It will beunderstood that the sodium diacetate, or other water soluble complexacetate of the type previously described, may be applied both to thewrapper and to the dairy product and may also be incorporated within thedairy product. The treatment of the outside of the dairy product may beaccomplished by dipping, spraying, or in any other suitable manner. Thesame is true with respect to the wrapper.

As previously indicated, the method of bringing the inhibitingcomposition into contact with the dairy product-may be varied ratherwidely. The inhibiting composition may be applied as a coating toparchment paper, foil (e. g., tin, aluminum and lead foils) and othertypes of wrappings. This method is particularly useful in treatingbutter. In treating cheese, the wrapping may be parchment. Pliofilm,Cellophane. cheesecloth and other similar wrapping materials. Here againth wrapping may be coated. Likewise, it will be understood that thebutter and cheese may be coated by dipping them directly into theinhibiting composition. The invention is not limited to any particulartype of dairy product but may be employed in treating not only cheeseand butter but also milk and derivatives of milk, including cream,powdered milk, powdered cream and buttermilk. In treating milk theinhibiting composition is dispersed in the milk. The same is true withrespect to cream. In treating powdered milk and powdered cream a smallamount of dry sodium diacetate or other complex acetate of the characterdescribed is dispersed with the powdered milk or powdered cream. Theamount will ordinarily be about 1 6% to about 2% by weight. In treatingbuttermilk the complex acetate is dispersed or dissolved in thebuttermilk in the same manner as for whole milk.

While the invention has been described specifically with reference tosodium diacetate because this is practically the only salt of this typeavailabl commercially today, it is also applicable to the other acetatesalts of a similar nature. A number of sodium acetate-acetic acid-watersystems are known to exist as mentioned by Bellstein, 4th edition, vol.II, page 107. Solid salts containing combined but undissociated aceticacid can be prepared containin from, say, 20% to 40% availableundissociated acid, but an acid sodium salt of acetic acid containingfrom about 25% to about 35% of available acetic acid is preferred forthe purpose of this invention. The sodium diacetate now availablecommercially is said to contain 33% to 35% available acetic acid with apH in 10% solution within the range of 4 to 5.5. Among the other complexacetates which may be employed in accordance with the invention are theother alkali metal complex salts such as the potassium salts. 1

It will be understood that the general aspects of the invention aredisclosed in our co-pending applications previously referred to. Theinvention is particularly advantageous in providing a method of treatingmilk products by incorporating into such products only a relativelysmall amount of an inhibiting composition which does not affect thetaste thereof and which at the same time is very effective, even whenused in such small amounts.

The expressions milk product and "dairy product" are employed herein todescribe generically products containing milk or derived directly frommilk, including whole milk, buttermilk, butter, cheese and other similarproducts.

Having thus described the invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

1. A composition'comprising butter and an alkali metal acetate saltcontaining combined but undissociated acetic acid in an amountcorresponding to about 0.1% to 2% by weight of said composition.

2. A dairy product selected from the group consisting of milk,buttermilk, butter, cheese, powdered milk, powdered cream and whey,containing a substantial quantity .of a non-toxic, water soluble alkalidiacetate, the quantity of said alkali diacetate being effective toinhibit the growth and development of bacteria and mold in said product.

3. A dairy product selected from the group consisting of milk,buttermilk, butter, cheese, powdered milk, powdered cream and whey,containing a substantial quantity of a non-toxic water soluble alkalidiacetate, the quantity of said alkali diacetate being within the rangeof about 0.1% to about 2% by weight of said prodnot.

4. A composition comprising a dairy product selected from the groupconsisting of milk, buttermilk, butter, cheese, powdered milk, powderedcream and whey, containing therein sodium diacetate in an amountcorresponding to about 0.1% to about 2% by weight of said composition.5. The method of treating a dairy product selected from the groupconsisting of milk, buttermilk, butter, cheese, powdered milk, powderedcream and whey, in order to inhibit the action of bacteria and moldtherein which comprises incorporating into said dairy product an alkalidiacetate in an amount corresponding to about 0.1% to about 2% :byweight of said product.

6. The method of treating a dairy product selected from the groupconsisting of milk, buttermilk, butter, cheese, powdered milk, powderedcream and whey, in order to inhibit the action of bacteria and moldtherein which comprises incorporatin into said dairy product sodiumdiacetate in an amount corresponding to about 0.1% to about 2 by weightof said product.

HANS F. BAUER. ELMER F. GLABE.

